The field of the invention is systems and methods for medical imaging. More particularly, the invention relates to systems and methods for co-registering medical images acquired with different imaging modalities.
Different imaging modalities have different strengths and weaknesses for visualizing different structures. For example, x-ray computed tomography (“CT”) is particularly good at imaging bony structures and magnetic resonance imaging (“MRI”) is particularly good at obtaining soft tissue contrast.
For surgical planning and intra-operative guidance, it can be desirable to simultaneously display information from multiple imaging modalities to leverage the benefits of each modality. For example, in orthopedic surgery the visualization of bones, ligaments, and tendons is important to the surgical intervention. The ability to register images obtained from different modalities can be challenging because images obtained with different modalities may depict different anatomical and physiological structures, such as bone versus soft tissue.
Thus, there remains a need to provide systems and methods that are capable of reliably combining image data from multiple modalities, such as CT and MRI, and displaying the results in an effective manner during an intra-operative procedure. For instance, the registration of multiple three-dimensional imaging volumes usually relies on the identification of common anatomic, or other, landmarks in each of the imaging volumes. When the imaging volumes have significantly different relative contrasts in these key structures (e.g., bone versus tissue), as is often the case with CT and MRI, the registration task becomes very challenging.